The present invention relates to a handling method and a jig for transferring a fusion-spliced optical fiber from a fusion splicing process to one of processes such as thermal treatment or reinforcing treatment of the spliced portion of the optical fiber.
After the fusion-splicing of a pair of single-fibers or a pair of multi-fiber units, the exposed spliced portion of the optical fiber is generally reinforced by recoating with UV-cured resin or covering with a heat-shrinkable tube. In case that a typical single-mode optical fiber and a specialty-functional optical fiber, which are different in mode-field diameter, are connected together by fusion, the resulting optical fiber cannot obtain a practically allowable splice loss without further processing its spliced portion. Therefore, in one of known methods, the spliced portion and neighboring portion thereof are further processed by heating to form a smoothly expanded taper core diameter such that the optical fiber has a matched mode field diameter at the spliced portion. This process is known as a method for obtaining thermally defused expanded core (hereinafter referred to as TEC method).
Thus, a fusion-spliced optical fiber must be transferred to each position for such processing of the spliced portion. In Japanese Patent Laid-Open No. 6-109946, there is disclosed a typical method for transferring a fusion-spliced optical fiber to a processing position for reinforcing its spliced portion.
According to the disclosed method, two processing means, one for fusion-splicing of two optical fibers and other for reinforcing the spliced portion of the spliced optical fiber, are arranged on one apparatus and the fusion-spliced optical fiber is clamped and transferred by a swinging arm to the neighboring processing position for reinforcing the spliced portion of the optical fiber by heating a heat-shrinkable tube put thereon. The above method is applicable for transferring the optical fiber merely between two positions: from the fusion splicing stage to the reinforcing stage.
However, when the fusion-spliced optical fiber requires high temperature heat treatment of its spliced portion (i.e. the TEC process), recoating and/or testing thereof, the apparatus becomes large and very expensive for such various processes since it is arranged as one apparatus. Furthermore, the above processes may vary depending upon the form of optical fibers to be fusion-spliced and hence require specially designed processing devices. This makes the apparatus unable to change or add processing devices and tools used thereon. In other words, the apparatus cannot be universal in practice.
In view of the above-mentioned circumstances, the present invention is directed to a handling method and a portable transferring jig for transferring optical fibers spliced by a fusion-splicer to separate processing apparatuses, at any time and at different places, for carrying out a necessary post-splicing processing of the fusion-spliced optical fibers. The term “post-splicing processing” as used herein includes heat treatment, coating process, reinforcing process, etc. performed after fusion-splicing optical fibers.
The fusion-spliced optical fiber must be held by clamps at a constant specified tension without sagging while it is transported to any separate processing place. The optical fiber must be held not to be subject to extension by heat while its spliced portion is thermally treated to form a necessary TEC. Furthermore, the method and device must have superior transferability without much labor so that necessary positioning can be exactly done at respective positions for various processes.
Therefore, the present invention is intended to provide a portable transferring jig and a handling method using the transferring jig, which can hold fusion-spliced optical fibers at a given tension and stop the tensioning of the fibers as needed and which is easy to transport and set up at any separate processing place. The term “given tension” as used herein means the tension that is sufficient for preventing an optical fiber from sagging, but not so high as may cause the optical fiber to break.